Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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Api to automatically check the status of a BTC transaction

My team is working for a community of members who make donations in BTC to support a cause from time to time. The donations the details are stored in a database and displayed on their personal ...
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Trying to locate my bitcoins

I was working with a broker, now my "bitcoins" are in "blockchain", and I have no trace. How do I find them? How do I find said blockchain and bitcoins ?
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How to sign Raw Transaction with Multiple Inputs

What is the procedure to sign a raw transaction with multiple inputs, i have some doubts, this is what i am doing: Step 1 First I serialize 1 unsigned tx for each input. INPUT 1 02000000 // Version ...
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1answer
15 views

Imported bitcoin address to block-chain un-spendable

I imported a bitcoin address to my block-chain wallet. The bitcoin shows as un-spendable in the wallet. The address was used previously by me and worked fine. How do i fix the problem to make the ...
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1answer
24 views

How to determine if BTC has been received from a particular address

I have been wondering if there is an api available that can enable me know if a certain amount of Bitcoin has been received from a particular wallet address. For the moment I have only be ...
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1answer
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How to find Reused R values

I use software from https://github.com/ca333/rng-scanner , I try to find r that is reused. from the software I found results Bitcoin Address : 1GQdrgqAbkeEPUef1UpiTc4X1mUHMcyuGW In Input NR : 141 ~ ...
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1answer
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How do bitcoin nodes agree who first mined ablock?

Once transactions are broadcast and a node starts working on a proof of work, and finds it, it broadcasts it to all other nodes for that block to be verified and added onto their blockchain. All nodes ...
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Bitcoin stuck in bitcoin core

Anaware of the fact that Bitcoin Core has to sync 800gb of data before showing up my coins, I transferred some money on a wallet created with the application. Now my money is stuck. The files are too ...
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1answer
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How a transaction is permanently accepted by the blockchain?

If a miner A creates a block containing a transaction A and a miner B creates a block NOT containing the transaction A about at the same time, then some of the other miners will first receive the ...
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Bitcoin Core wallet fails to load and requires reindex after I already did it

My Bitcoin Core is synchronized. But I can't open a wallet, it says that I might need a reindex. Though I already did it. Also I can't do dumpprivkey because it says that no wallet is loaded. How can ...
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How to create block height to UNIX time converter?

I want to create a converter that can be given a block height, human readable time, or UNIX time and then provide the correlated information for it. For example, if given a block height, the converter ...
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1answer
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How can I receive money sent to a used address [closed]

I sent money to a blockchain wallet address which had once been used to receive money. Now money is not found in the account. What do I do to recover the money. Thanks
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What’s prevents people from appending useless blocks to very old blocks in order to revert new transactions? [duplicate]

As far as my understanding goes, nodes in the network should accept the longest branch of blocks and disregard any other branches (excuse my terminology if it’s not what’s normally used - I hope it is ...
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Creating a Locking Script

What will be the script like for a situation like this: Lets say Alice and Bob are 2 parties. Alice has a password which Bob wants. Alice will only give Bob the password if Bob pays 5BTC to Alice. ...
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1answer
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How can I create the input of raw transaction through the previous UTXO hash and the unspent index in bitcoinj?

I want to create a raw transaction’s input and output, and sign it then broadcast to testnet. Now I know how to create the output, but I want to refer the transaction that I can input the UTXO hash ...
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2answers
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possible victim of non-spendable scam

A bitcoin trader opened a blockchain wallet for me and then sent me my profit but it is non-spendable. I know they can no longer get into my account because I changed the password and I have two-step ...
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2answers
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Block 620826 is 1 second before block 620825?

How does that happen? Obviously the miner of 826 built his block on top of 825, but why is the time 1 second earlier?
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Could a computer virus made less than a mb, which is sent as transaction that attacks miners? [closed]

What happens if computer virus less than a mb is sent as transaction that attacks miners?
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What will a miner do when a high-fee transaction comes but he has constructed his block and is solving the puzzle?

As far as I have known, the mining process is as follows, step 1: collect a series of transactions and construct a block by filling required information like hash of the previous block and the ...
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1answer
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Block construction

I'm in the process or preparing a lecture on cryptocurrency and have studied dozens of sources. I have a pretty good understanding of most aspects of the bitcoin blockchain scheme. However, all of ...
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1answer
35 views

How to download bitcoin blockchain without core?

I tried to download the entire blockchain using bitcoin-core but i took about 9 days and eventually gone corrupted and i had to delete and restart. Any source to download through torrent or regular ...
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1answer
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How Do They Get BTC Wallet.dat With Balance?

Going through YouTube, I found some videos on Bitcoin wallet.dat with balance. Looking at these videos, you will notice that these balances found in these btc wallet.dat are not on watch only ...
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Configure esplora to point to the bitcoind servers ip address - Part 3

Continuing on from this post: Configure esplora to point to the bitcoind servers ip address - Part 2 Trying to run cargo run --release --bin electrs -- -vvv --daemon-dir ~/.bitcoin, but it kept ...
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2answers
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How to transfer blockchain between two machines?

I have two computers A and B. A has a partial history of bitcoin blockchain (about 60% of entire history) which is not pruned (~120GB). I would like to transfer the history to B and run a pruned full ...
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How we can use Blockchain to prevent Plagiarism in scientific papers? [closed]

I have a research in "plagiarism prevention using blockchain" topic, and it is specialized in scientific papers. Anyone has any idea to help me through this topic?
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1answer
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How do I get my Bitcoin “Spendable” instead of it being “Non-Spendable” on my Blockchain Account? [closed]

I have been fighting this all night and day and haven't made any progress. I used a CoinFlip ATM to buy BitCoin or deposit USD into the machine. I have an account at Blockchain and I used the right QR ...
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2answers
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How Do Attackers Forge Bitcoin Blocks And How Do You Identify Forge Bitcoin Blocks? [duplicate]

I have read that a block contains several bitcoin transactions and an attacker can forge fake blocks. Does these forged fake bitcoin blocks cost the attackers money for mining or was it just ...
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1answer
49 views

Configure esplora to point to the bitcoind servers ip address - Part 2

Continuing on from this post: Configure esplora to point to the bitcoind servers ip address Trying to run cargo run --release --bin electrs -- -vvv --daemon-dir ~/.bitcoin, but it kept saying that ...
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2answers
53 views

How to check if a bitcoin address received a new transaction programmatically?

How can I check if a bitcoin address received a new transaction programmatically? Here is an example of the API call, but I can't figure out how to get the value of the new transation in API response:...
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3answers
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How To Create BTC Raw Transactions With 0 BTC Wallet And Broadcast It On Blockchain Network? [closed]

https://www.youtube.com/watch?v=2NFMMNXyHNE I watched a YouTube video of someone that created several BTC raw transactions with 0 BTC Wallet and broadcasted it on blockchain network with valid ...
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1answer
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How do people using thin clients know the correct merkle path of transactions they've sent without knowing the full block?

User A send a transaction to user B. Those transactions are bundled together into a merkle tree. User A and B can both use the transaction plus the merkle root, plus the merkle path to prove the ...
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Sent bitcash to bitcoin coin address given by coinfy from my bit wallet can they trace funds and return them or is it impossible [duplicate]

Hi I sent bitcash instead of bitcoin to coinfy bit coin address they gave by mistake should of bitcoin.. it's completed hash tag etc.. I was told the mix up was from my wallet to them (being new to ...
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1answer
56 views

What does best block time mean in wallet.dat

I have a wallet.dat file that states: Best block at time of backup was 42603 (0000000013136bd812212959a15ef0ea0f084ee2c64e2f7f0e127d198f67a37f), mined on 2010-02-26T00:36:08Z Does that mean that one ...
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0answers
21 views

Noob question, how do nodes know about other nodes [duplicate]

I'm new to the p2p tech and I would like to figure out how it is working. How a new node knows ip addresses of other nodes, if there is no server? Writing classic software we usually hardcode a server ...
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1answer
28 views

Calculate Transaction Confirmations

I am writing an API for one of my systems which can verify if a monitored address is receiving Bitcoin, I can already check if the address is on the newly received block, save it to a database for ...
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1answer
49 views

block verification cost

When a node receives a block, is it enough to validate root of Merkel tree ? How does block size affect the validation cost? What is the difference between the cost of validation 1mg-size block and ...
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Fork rate range in terms of network security

I am really new to bitcoin and am trying to understand the basics. Fork rate/Orphan rate is a measure of network security. The higher the fork rate, the more compromised the system. Also fork rate ...
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1answer
27 views

how is litecoin different from bitcoin [closed]

So far, i only know that litecoin is using another mining algorithm called Scrypt which has some ASIC resistance. Is there any more difference? Or they are completely the same except the mining ...
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1answer
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How do i have a 2011 bch transaction?

I was under the impression that BCH did not fork untill 2017. How was i making transactions in 2011?
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1answer
67 views

How do I get wallet balance using xPub address with blockain.info api? [closed]

I am using blockchain.info api. I know how to get wallet balance using wallet id and password. Couldn't find how to find wallet balance using my xPub address.
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1answer
131 views

Unspendable bitcoins on blockchain [closed]

Gooday, please i want to know how to transform my non spendable bitcoins to spendable bitcoins on blockchain account for the sake of being able to spend them please someone help me out I'm lost. I ...
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1answer
44 views

Storing Provenance details in Bitcoin Blockchain

I am quite new to the blockchain and bitcoin world. I was looking at some ProofOfExistance (PoE) solutions (Digital Notary) for documents. While these solutions store the hash of document+timestamp, ...
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Double spending problem 2.0 [duplicate]

How is the following case handled in bitcoin blockchain? Initially Alice has only 2 bitcoins. Suppose Alice sends 2 bitcoins to herself(tr1 i.e. Alice to Alice) and then 2 bitcoins to Bob(tr2 i.e. ...
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1answer
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How does bitcore-node get its data?

I'm trying to understand how does bitcore-node, the javascript implementation of Bitcoin protocol, get its data? Can it connect to Bitcoin Core, the original C++ implementation of the Bitcoin protocol,...
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1answer
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How do miners communicate in Bitcoin/ Decentralized Network?

1.)If there is no central authority maintaining database how miners differentiate among other miners. 2.)Do they have there own database which have details(Mac/IP address) of neighbouring miners . 3....
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3answers
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Can a miner just introduce a block full of valid predetermined transactions in the blockchain and get rewarded?

My question is - let's say a miner has control over a certain number of bitcoin addresses. He creates a block containing small transactions to and fro from these accounts ahead of time in advance and ...
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IBD problem: Reindexing blocks and syncing starts over every time I shut and open Core

I am currently doing IBD in segments due to logistical reasons, but each time I safely shut down Core and unplug my hard drive (HDD, 1TB) and then plug it back in and start up Core, it starts in 2009 ...
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Is there a way to know at any point in time T how many BTC exist that were bought at time t<T?

What I would like to find out is whether for a specific time in the past, we can know the number of BTC that exist today and were bought at this time. The discrete time can be the time of block ...
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3answers
58 views

Does the btc price depend on the reward?

Hey guys if you answer this question that I am keeping from months ill be happy. Does the actual bitcoin price depend on the mining profitability? So is it more profitable mine when the price is ...
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1answer
72 views

How to monitor Bitcoin address for new transactions?

I have some generated Bitcoin addresses which I want to monitor for newly received transactions, I have a full node but I don't want to import those addresses to the node's wallet. I don't want to use ...

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